The meme of course while capturing the spirit did not get the sword right. It looks like a dagger or short sword to me so I looked it up.

The blade used by Otoya Yamaguchi to assassinate Inejirō Asanuma on October 12, 1960, is properly described as a wakizashi, a traditional Japanese short sword.

Specifically, the weapon was a 33-centimeter (13-inch) replica wakizashi that Yamaguchi had stolen from his father. Some sources also refer to the blade as a yoroi-dōshi (armor piercer), a type of short sword traditionally used by samurai for close-quarters combat and piercing armor, which Yamaguchi selected for its concealability and lethality in grappling. The assassination was captured on live television and in a Pulitzer Prize-winning photograph by Yasushi Nagao